← All patterns
Cavitary lung lesion
ChestCT / Radiograph
A gas-containing space within a nodule/mass or consolidation. Wall thickness and clinical acuity are the strongest predictors of aetiology.
Differential
Lung abscess
common- •Thick irregular wall with air-fluid level
- •Acute febrile illness, aspiration risk
- •Dependent (posterior/basal) location
Post-primary tuberculosis
common- •Upper-lobe / apical posterior segment
- •Surrounding tree-in-bud and satellite nodules
- •Relatively thin, smooth cavity wall
Cavitating squamous cell carcinoma
common- •Thick (>15 mm) irregular nodular wall
- •Spiculated outer margin, no air-fluid level
- •Smoker, associated adenopathy
Septic emboli
less-common- •Multiple peripheral cavitating nodules
- •Feeding-vessel sign
- •Endocarditis / IV drug use
Granulomatosis with polyangiitis
rare- •Multiple cavities of varying wall thickness
- •c-ANCA positive, renal/sinus involvement
Pulmonary infarct (cavitating)
rare- •Peripheral wedge shape with reversed halo
- •Filling defect on CT pulmonary angiogram
Key discriminators
- •Maximum wall thickness (thin <4 mm benign; thick >15 mm malignant)
- •Wall regularity (smooth vs nodular/irregular)
- •Air-fluid level (favours abscess)
- •Single vs multiple cavities
- •Distribution and clinical acuity
Work-up / next steps
- 1.Sputum/blood cultures and TB work-up
- 2.Contrast CT to assess wall and surrounding lung
- 3.Bronchoscopy or biopsy if malignancy suspected
- 4.ANCA serology when multiple cavities
References
- Radiopaedia: Cavitating lung lesion.
- Woodring JH. Cavity wall thickness in the differentiation of benign from malignant cavities. AJR.
Educational clinical decision support only. This differential does not make a diagnosis, is not a medical device, and must never substitute for interpretation by a qualified radiologist correlated with the full clinical picture and prior imaging.